(a) Fields of the Invention
The present invention relates to semiconductor devices and their fabrication methods.
(b) Description of Related Art
In growing a semiconductor layer on a substrate, crystal growth of the semiconductor may be conducted on an indented surface of the substrate. For example, a crystal of a semiconductor layer is grown on a substrate with fine indentations, whereby the crystallinity of the formed semiconductor layer is improved. This provides a semiconductor device with excellent characteristics (see, for example, Japanese Unexamined Patent Publication No. 2002-289540).
For a semiconductor light emitting diode (LED), a photonic crystal having two-dimensionally periodic indentations in an emitting surface thereof can be provided to improve the light-extraction efficiency of the diode. The photonic crystal can be formed easily by growing a semiconductor layer on a substrate having two-dimensionally periodic indentations (see, for example, Japanese Unexamined Patent Publication No. 2006-049855).